Over the past decade, investigators have come to recognize the importance of the extracellular matrix (ECM) in directing the growth, differentiation and function of the overlying epithelium. Getzenberg et al., "The Tissue Matrix: Cell Dynamics and Hormone Action", Endocrine Rev , 11: 399-417 (1990). The interaction between cell and extracellular matrix (or substratum) is mediated by several classes of cell adhesion molecules, one of the most important being the integrins. Albelda et al., "Integrins and Other Cell Adhesion Molecules", FESEB J., 4: 2868-2880 (1990). Buck et al., "Integrin, a Transmembrane Glycoprotein Complex Mediating Cell-Substratum Adhesion", J. Cell Sci. Suppl., 8: 231-250 (1987). This diverse family of glycoprotein receptors is expressed on the cell membrane as heterodimeric .alpha. and .beta. subunits and is involved in both cell-cell and cell-substratum adhesion. Specific recognition and binding of extracellular matrix (ECM) components such as fibronectin (FN), laminin (LM) and collagen (Col) transmit information to the cytoskeletal structure, an interaction which may have major roles in promoting hormone responsiveness and genomic activation. Burridge et al., "Focal Adhesions: Transmembrane Junctions Between the Extracellular Matrix and the Cytoskeleton", Ann Rev. Cell. Biol. 4: 487-525 (1988) and Getzenberg et al. supra.
Although extensive information exists about specific integrin proteins, for example, Hemler, M. E. "VLA Proteins in the Integrin Family: Structures, Functions and Their Role on Leukocytes", Annu. Rev. Immunol: 365-400 (1990), little is known concerning the distribution of these receptors in the female reproductive tract. In the uterus, the endometrium, composed of glandular epithelium and associated mesenchyme (stroma), maintains complex temporal and spatial functions in response to the cyclic hormonal milieu. The search for morphological or biochemical markers for uterine receptivity has been unsuccessful to date as reported by Rogers and Murphy, "Uterine Receptivity for Implantation: Human Studies", in Blastocyst Implantation, Yoshinaga, K. ed., Serono Symposia, pp. 231-238 (1989). Once such markers are identified, their role in endometrial phenomena including embryo implantation, fertility, contraception and endometrial maturation and receptivity can likely also be identified. Thus, as some integrins appear to meet the criteria for markers of receptivity there is a great need for methods of detecting integrin cell adhesion molecules in endometrium.